LED驱动器提高电池寿命的物联网便携式设备

LED驱动器提高电池寿命的物联网便携式设备

　　便携式产品制造商正在不断寻找方法，以减少电力需求，以最大限度地提高电池寿命。随着对物联网的运动，以及智能手机，如网络控制和监测目的的智能设备的普遍使用，需要提高功率效率已变得更加迫切。便携式设备上的LED背光可以占总有源系统功率的一个重要部分。LED背光驱动器可单独使用高达40%，使其成为节能工作的首要目标。

　　采用各种技术，以减少背光功率消耗。选择LED驱动器IC已被优化为低功耗和效率是一个明确的起点。如环境光传感器和动态背光控制结合调光技术可以作出重要贡献，节约电池电量。

　　Figure 1： Dynamic backlight control uses dimming to save battery power， such as when using a smartphone in the dark.

　　This article will consider the contribution thatcanbe made through advanced design and the judicious choice of the LED driver. Factors under scrutiny include topology， the characteristics required to support additional power saving techniques， and their impact on efficiency and circuit size.

　　Reference will be made to theRichtekRT9285 boost converter， ideal foroperation from a single cell li-ion battery， and from Texas Instruments， the LM3530 current mode boost converter which can drive a single string of up to 11 LEDs and the LM3532 and LM3697 for driving three LED strings.

　　For ultra-low power and wearable devices， low dropout （LDO） regulators with charge pumps， such as the RT9361 from Richtek， are an option， or buck-boost regulators including the RT6150A/B or the ISL9111 fromIntersil.